The process of détente in the 1970s reduced tensions between the USA and USSR for a time. There were four main reasons for détente: 1) The Vietnam War weakened US confidence and made it wary of overseas wars, 2) Both countries faced economic problems that made continuing an arms race unaffordable, 3) Leaders feared nuclear war after events like the Cuban Missile Crisis showed the risks, and 4) Improving US-China relations worried the USSR and motivated it to seek better relations with the USA as well.